There were 68 thyroids with oncocytic cell changes among thyroid specimens from 2476 thyroid operations performed between 1969 and 1978. In 12 instances there were merely Hürthle cell nests, in 13 there was an oncocytic carcinoma and in 43 oncocytic adenoma. Thyroidectomy was the preferred treatment for Hürthle-cell carcinoma. Five patients were no longer suitable for radical operation, in one there was a recurrence. If there is a potentially malignant oncocytoma, hemithyroidectomy should be performed and careful follow-up is necessary. There was no recurrence maximally 82 months postoperatively.